Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 9,191	$ (7,506)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment, net of tax $0 and $0, respectively	410	(712)
Retirement plan liability adjustment, net of tax $0 and $0, respectively	(569)	(3,968)
Comprehensive income (loss)	$ 9,032	$ (12,186)